slow dhcp on 1G backbone.
Simon Hobson
dhcp1 at thehobsons.co.uk
Fri Jul 24 14:39:40 UTC 2009
Glen R. J. Neff wrote:
>What kind of switch? How are the ports configured?
>
>I know some Cisco switches will default to having trunking and
>channeling turned to auto by default, and having portfast turned off.
>Any of these can hinder DHCP's function.
Good point - I've seen slow or broken DHCP when switches have
Spanning Tree set. When a device is connected, Spanning Tree will
default to disabling traffic on the port while the switch learns the
new topology - IIRC portfast (and Rapid Spanning tree on some
switches) forces the port to active state at the slight risk of a
temporary loop if the new device is another switch.
Some devices will give up on DHCP before the port is enabled for
traffic, others will have dropped back to long retry periods.
--
Simon Hobson
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